Multiple contact lamp hanger



Jan- 19, 1954 R. K. FARRINGTON ETAL MULTIPLE CONTACT LAMP HANGER Filed Sept. 15. 1950 Y I' 121/D "2" 1 Y 'i .ffflr- 14 N im .5 n llm I nl m' l"l-,ll any I //////%/,|m1 2 f Q 'EL 52 I u, `\\\\\\\\\\\.L

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INVENTORS Patented `ian. 19, 1954 UNITED STATES PATENT OFFICE MULTIPLE CONTACT LAMP HANGER Application September 15, 1950, Serial No. 184,954

4 claims. 1

This invention relates to lamp hangers having multiple contacts and in particular to such devices having means for equalizing the pressure between the contacts.

An object of the present invention is to provide means for supporting separable contacts in a simple but emcient manner providing for the necessary adjustment of the coacting pairs of contacts when making and breaking the circuit.

In the drawings,

Fig. 1 is a side elevational view, partly in section along the line I-I of Fig. 2, showing an embodiment having six pairs of coacting contacts;

, Fig. 2 is a sectional View on the line 2-2 Fig. 1 and partly broken away;

Fig. 3 is an end elevation of the embodiment of Figs. 1 and 2; and

Fig. 4 is a sectional view taken on the line 4 4 'Of Fig. 2.

It is to be understood that although a preferred embodiment of the invention is hereinafter described in detail, the invention is not limited to such embodiment unless so defined by the appended claims. In addition, the terms and phrases used herein are merely descriptive and illustrative and are not to be construed as in any way limiting the invention. V In the present state of the illumination art, there is a definite need for lamp fixtures adapted to provide a multiplicity of circuit contacts in a single ixture. There are many applications for such xtures in which it is necessary or desirable to have several circuits, such, for example, as in eliminating stroboscopic effects, and in step or progressive starting.

In many applications, it is necessary or desirable to mount the xtures on the ceiling, and, when the ceiling is high, maintenance diiculties are encountered unless the iixtures can be lowered to a convenient level. The present invention is adapted for use with any one of a number of lowering devices, one of which, for example, is that described in the copending application of Thayer B. Farrington et al., Serial No. 184,686 iiled September 13, 1950.

Speaking first generally, there is illustrated an embodiment of the invention having six pairs of coacting contacts. A iixed member, which is normally attached to a ceiling fixture, has six fixed contacts mounted thereon in two groups of three respectively on each side of the center. A separable element also has six contacts which coact with the six fixed contacts and are adjustably mounted with respect to each other. The

groups of three contacts on the separable element are mounted one group at each end of a lever, pivoted intermediate its ends. Each group is mounted on the lever by a ball and socket arrangement, thereby providing means to equalize pressure between the three contacts of the group. Therefore, any irregularities in the mountings of the ixed contacts will be compensated for and iirm engagement between all pairs of contacts obtained. In addition, should the separable element be tilted when drawing the two elements together, the pressure between al1 pairs of contacts will be equalized and no damage will result.

Referring to the drawing, the fixed member I0, which is normally secured to a ceiling fixture or other support, comprises a plate II to which the insulator blocks I2 are attached by bolts and nuts as at I3. Each block I2 has three downwardly projecting portions I4 to each of which is secured contact means, in this case, a cup-shape downwardly opening contact I5, attached by a bolt I6 and nut I1. A terminal lug I8, of soldered or solderless type, to which an electricai lead may be attached, is retained on each bolt I6 between the contact I5 and the insulator projection I4, and extends outwardly from the protecting skirt Ida on each insulator portion I4. The downwardly projecting portions I4, in this embodiment, are arranged at the corners of a triangle having its base toward the center of the fixed element and at right angles to the longitudinal center line of the element. However, it is not necessary that the triangle be oriented in this or in any particular manner, and the arrangement described herein is merely for illustrative purposes and is not to be construed as limiting in any sense.

The separable element, designated generally by the numeral 20, comprises in general a bracket having a lever pivoted thereon. The bracket 2| is substantially rectangular and has two downwardly extending skirts 2 Ia and two upstanding lugs 22, for the purpose to be hereinafter described. As previously mentioned, the present invention is adapted for use with lowering fixtures. and, therefore, iittings 23 are provided in the center portion of the bracket 2I. The ittings 23, and a platform spring to be later described, act in conjunction with the lowering xture to which the bracket is generally attached, as shown in the above mentioned copending application Serial No. 184,686, and provide guide means to produce vertical alinement of contactsV 36 respectively with contacts I5, and provide latch means to connect and disconnect the xed and separable portions of the xture. Similarly functioning guide and latch means are shown in the copending application of Thayer B. Farrington et al. Serial N0. 589,322 filed April 23, 1945, and since issued as U. S. Patent No. 2,554,328, August 14, 1951.

A lever 25 is pivotally mounted between the upstanding lugs 22 on the bracket 2l. Two lugs 2B on the lever 25 have screws 2'! threaded thereinwhich ride in slots 22a in the lugs 22J thereby defining an axis about which the lever 25 may pivot. The central portion of the, lever 25 is apertured as at 25a to provide access to the lit;- tings 23. A cup-shape upwardly opening depression 28 is formed in each end portion of the leve 25 and will be hereinafter referred to as a socket, for descriptive purposes. ln the center of each socket 28 is a non-circular aperture 28a (here shown as square) into which loosely nts a complementary projection 33d to prevent any rotation of block 33 which would carry contacts 35 out of mating engagement with contacts l5. Platform springs 2QA disposed between the bracket 2l and the lever 25 on each side of the pivotal axis (defined by the screws 2l) maintain the. lever 25.

manner of the usual ball and socket joint, and

the projection 33a extends through the aperture 28a which is somewhat larger than the projection to permit oscillation of the ball-and-sockct joint. A retaining washer or ange 36, carried by or attached to a screw 35 which is threaded into the projection 33a, retains the spherical surface S3 in position in the socket Eil-and yet allows bearing movement between the two surfaces. Contact means are carried by each insulator block 32, and, in this instance, comprise self-centering contacts 36 mounted one on each corner of; each of the triangular insulator blocks 32 in position to meet and coact witha corresponding fixed contact l5. The surface of each Contact 3,6 is substantially a spherical segment, complementary to the surface of each contact i5. A bolt 3 7 extends 'through a holeA 32h under each contact 35 and the lock nuts 38a and 38D retain the boltand contact in position. As seen in Fig. 1, the holes 32h are somewhat larger than the boltssl, and the lock nuts 38u and 3813 are not drawn tightly against the insulator blocks 32. Thus, because` some movement of each individual` contact 3S is allowed, the contact will cam into engagement with the iixed contact and center itself therein. An electrical lead may bev retainedy between the lock nuts 38a and 38h and will be protected by downwardly extending skirts 32a.

It is a well known geometric principle that a plane is deiined by three points. Applying that principle to practice, it is seenthat even` though the three contacts comprising each o f theI two xed groups may not lie in aplane parallel to the plate ll due, perhaps, to defects in mounting, they will all three lie in son-ieone particular plane. Therefore, since the separable element contacts are mounted by means of the ball and socket arrangementsl previously described, the plane dened by the three-.contacts of each separable element group can be mader to lie parallel to that dened by the xed element group. Thus, rm contact is obtained between coacting contacts of all three pairs when the fixed and separable elements are drawn together. It is apparent that this parallel plane adjusting action will take place in both groups of three contacts mounted on opposite ends of the lever 25, and, because of the pivotal mounting of the lever 25 on the screws 21, a further equalizing action will take place between the two groups. That is, should the plane defined by the three contacts of one group be higher than that dened by the other group, the lever 25 will pivot about the screws 21 to equalize pressure between coacting contacts of the twol groups. The platform springs 29, of course, aid in obtaining firm engagement between contacts of all mating pairs. It should be noted the ball and socket mounting need not be placed at any particular point other than within the boundaries of the triangle dened by the contacts 3B. In the embodiment illustrated, the mounting is placed approximately at the center of the triangle, but this is in no sense to be construed as a limitation and the same principles of operation apply regardless of the mounting location with the triangle.

It is apparent that the present inventionprovides a device which will operate efficiently and which is simple in construction. Various changes may be made by one skilled in the art without departing from the spirit of the invention or the scope of the appended claims.

What we claim is:

1. Lamp hanger contact supporting means comprising bracket means, a lever having a pivotal mounting on said bracket means intermediate the ends of said leverr at right angles and intermediate the longitudinal center line of said bracket, a pair of insulator blocks positioned one at each end of said lever, each end of said lever having a ball and socket connection with its associated insulator block including coacting ball and socket parts on saidlever and said insulator block, and three contacts carried by each said insulator block in triangular relationship on each block.

2. Lamp hanger contact supporting means comprising bracket means, a lever having a pivotal mounting on said bracket means intermediate the ends of said lever at right angles and intermediate the longitudinal center line of said bracket, a pair of insulator blocks positioned one at each end of said lever, each end of said lever having a ball and socket connectionrwith its associated insulator block including coacting ball and socket parts on said lever andv said insulator block, and three contacts in triangular relationship carried by each said insulator block, said ball and socket connection being located within the triangle defined by said` three contacts.

3. Lamp hangervcontact supporting means for pressure coaction with two sets of. complementary contacts arranged in twogroups of` three each, said meansk comprising bracket means, a lever having a pivotal mounting on said bracket means intermediate the ends of said lever at right angles and intermediate the longitudinal center-line", of said bracket and having an upwardly opening socket element in each end thereof, a pair of in,- sulator blocks each having a downwardly pro-r jecting ball element thereon, each said ba11 element being'seated in one said socket element, means for adjustably retaining each said ball element in its corresponding socket element, such means comprising a projection on each said ball element which extends through an aperture in said corresponding socket element and is retained therethrough by a washer on a bolt threaded into said projection, and three -contacts in triangular relationship carried by each said insulator block, each said contact being mounted thereon by means of a bolt extending through its associated said block through an aperture of larger diameter than said bolt, said ball element being located within the triangle defined by said three contacts, whereby to center each contact with its coacting one, to equalize pressure between said three contacts on each said block, and three of said complementary contacts and to equalize pressure between said blocks mounted on opposite ends of said lever against said two groups of complementary contacts.

4. In the combination of a plurality of fixed electrical contacts and a plurality of movable electrical contacts adapted to mate with the fixed electrical contacts respectively, movable lamp hanger contact supporting means comprising bracket means, a lever having a pivotal mounting on said bracket means intermediate the end of said lever, a pair of insulator blocks positioned one at each end of said lever, each end of said lever having a ball and socket connection with its associated insulator block including coacting ball and socket parts on said lever and said insulator block, three contacts carried by each said insulator block and adapted to mate with coacting xed contacts, each pair of mating contacts having coacting convex and concave mating surfaces respectively, said ball and socket connection being located within the triangle deiined by said three contacts, a non-circular projection on each of said ball parts, there being a, non-circular opening through each of said socket parts adapted to receive one of said non-circular projections loosely, means securing each coacting ball and socket part against separation,said loosely tting projection and associated opening permitting insufficient movement of said movable contacts out of mating engagement with said xed contacts, means providing approximate vertical alignment between said xed and movable contacts, and means for retaining said mating contacts in engagement.

ROBERT K. FARRING'ION.

THAYER B. FARRINGTON.

RICHARD F. KURZENBERGER.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 760,591 Warner May 24, 1904 973,558 Pierce Oct. 25, 1910 1,223,532 Thompson Apr. 24, 1917 1,552,654 Thompson Sept. 8, 1925 2,369,860 Schroeder Feb. 20, 1945 2,377,872 Farrington June 12, 1945 

